PG_STAT_ALL_INDEXES

PG_STAT_ALL_INDEXES contains one row for each index in the current database, showing statistics about accesses to that specific index.

Indexes can be used via either simple index scans or “bitmap” index scans. In a bitmap scan the output of several indexes can be combined via AND or OR rules, so it is difficult to associate individual heap row fetches with specific indexes when a bitmap scan is used. Therefore, a bitmap scan increments the pg_stat_all_indexes.idx_tup_read count(s) for the index(es) it uses, and it increments the pg_stat_all_tables.idx_tup_fetch count for the table, but it does not affect pg_stat_all_indexes.idx_tup_fetch.

Table 1 PG_STAT_ALL_INDEXES columns

Name	Type	Description
relid	oid	OID of the table for this index
indexrelid	oid	OID of this index
schemaname	name	Name of the schema that the index is in
relname	name	Name of the table for the index
indexrelname	name	Index name
idx_scan	bigint	Number of index scans initiated on the index
idx_tup_read	bigint	Number of index entries returned by scans on the index
idx_tup_fetch	bigint	Number of live table rows fetched by simple index scans using the index